Conventionally the pour point reduction of petroleum hydrocarbon stocks has been accomplished by blending the high pour hydrocarbon with a low pour distillate by the addition of pour point depressants or by the low temperature solvent extraction of waxy components from the high pour hydrocarbon. The latter process is an expensive operation and is generally reserved for lube oil fractions.
Recently, British Petroleum has publicized the use of a catalytic process for dewaxing lube oils. The British Petroleum process, as described in U.S. Pat. No. 3,516,925, employs a dual-function shape-selective zeolite hydrocracking catalyst consisting of platinum on H-mordenite to selectively hydrocrack normal or near-normal paraffins.
Although catalytic dewaxing processes such as proposed by British Petroleum appeared to be attractive when compared to the relatively expensive low temperature solvent extraction processes presently being employed, the commercial feasibility of any catalytic dewaxing process can be established only after the process has been found to be generally applicable to conventional refining streams and only after the catalyst has been found to be commercially stable.